Electronic discharge tube



Aug. 7, 1962 E. PAUL, JR

ELECTRONIC DISCHARGE TUBE 2 Sheets-Sheet 1 Filed Oct. 27, 1960 EDWARD PAUL JR.

INVENTOR.

ATTORNEYS 7, 1962 E. PAUL, JR 3,048,739

ELECTRONIC DISCHARGE TUBE Filed Oct. 27, 1960 2 Sheets-Sheet 2 FIG. 8

EDWARD PAUL JR.

IN VEN TOR.

ATTORNEYS United States Patent the Navy Filed Oct. 27, 1960, Ser. No. 65,551

12 Claims. (Cl. 313-220) (Granted under Title 35, US. Code (1952), see. 266) The invention herein described may be manufactured and used by or for the Government of the United States of America for governmental purposes without the payment of any royalties thereon or therefor.

The present invention relates to electronic discharge tubes, and more particularly to a thin flat or curved discharge tube in which high excitation is obtained by making the walls of the tube in very close proximity to each other.

Earlier type tubes consisted of a section of glass or silica tubing of substantial cross section into which a suitable quantity of gas was sealed, followed by excitation by a microwave beam, or in the case of a tube with elec trodes by excitation by a transformer. However, the prior art electrode discharge tubes favored mainly low stages of excitation, and were unsatisfactory for use in spectrometry since only a small cross section of light from the end of such a tube could be used on the slit of a spectrometer.

The present invention which is very flat favors the development of series spectra, and may be used with a microwave exciter. The present tube can be used with any type excitation to increase the amount of energy that falls on the slit of a spectrometer by using the thin line of light from one end thereof. This unique flat light source is readily adaptable for use in fluorescent or filament lights and for special lighting eifects.

It is an object of the invention, therefore, to provide a novel thin flat discharge tube;

It is another object of the invention to provide a new and improved discharge source for providing high stage excitation for use in spectrometry;

Another object of the invention is to provide a new and improved thin light source.

A further object of the invention is to provide a novel flat light source structure for use in fluorescent and filament lights.

Still another object is to provide a novel light source having a thin flat or curved cross-section.

A still further object is to provide a new and improved microwave-excited electrodeless discharge source.

Other objects and many of the attendant advantages of this invention will become readily appreciated as the same-becomes better understood by reference to the following detailed description when considered in connection with the accompanying drawings wherein:

FIGURE 1 is a plan view of a preferred embodiment of a thin electrodeless flat tube of the present invention;

FIGURE 2 is a cross-sectional view taken along line 22 of FIGURE 1;

FIGURE 3 shows a cross-section of another embodiment of the thin portion of the tube of FIGURE 1 where the thin portion is curved rather than flat;

FIGURE 4 shows a plan view of another embodiment of the invention in which a filament may be used;

FIGURE 5 shows two embodiments of cross-sections taken along line 55 of FIGURE 4;

FIGURE 6 illustrates a Geissler tube having a thin flat or curved mid-section;

FIGURE 7 is a cross-sectional view taken along line 7-7 of FIGURE 6;

FIGURE 8 is a plan view of a fluorescent type tube of the present invention;

Patented Aug. 7, 1962 FIGURE 9 is a cross-sectional view of FIGURE 8 taken along line 9-9.

Referring now to the drawings like numerals refer to like parts in each of the figures.

The embodiment illustrated in FIGURES 1 and 2 comprises a length of flat glass or silica tubing 10 having a gas reservoir 12 attached at the side of one end thereof. The interior of the flat portion 10 of the tube has a very narrow slit-like cross-section 14. As shown in FIGURE 3 this portion may be made curved for special purposes.

No doubt many methods may be used to fabricate a thin flat or curved tube of the type described herein; however, one method is to choose a section of quartz tubing and insert therein a very thin (e.g. inch) flat strip of tungsten that is long enough and wide enough to fit within the section of tubing. Then the quartz tubing heated and flattened against the tungsten strip. The tungsten strip is then removed when the flattened tube has cooled. In many instances the tungsten strip will pull out easily; if not, it may be necessary to place the tube in an acid until the tungsten strip comes loose and can be removed. With the tungsten strip removed, the product is a flat tube 10 with a long and very thin slit 14 down the center, see FIGURE 2 for example. The width and length of slit 14 can be varied to suit any requirements. For use with a curved-slit spectrometer the crosssection of the slit may be curved as shown in FIGURE 3. Materials for making these tubes may be varied and should depend upon the application thereof.

The flat or curved tube of the present invention has a very small gas capacity and therefore a gas reservoir, such as 12 in FIGURE 1, is needed therewith, as previously mentioned.

Another modification of the present invention is shown in FIGURES 4 and 5 which illustrates a circular tube 16, for example, which can be made with a flat or curved cross-section having a thin cavity 18 therein. Obviously this type of tube could be made in a variety of configura tions other than circular.

A further embodiment is shown in FIGURES 6 and 7 in which a Geissler tube is illustrated using a flat tube 20 connecting the two reservoirs 22 and M- containing electrodes 26 and 28 respectively. The slit-like passage 29 may be made curved as shown in FIGURE 3 if desired.

Also, as illustrated in FIGURES 8 and 9, the present invention can be applied to fluorescent lighting. A thin curved tube section 30 having terminals 32 and 34 on opposite ends thereof can be silvered or coated on one wide side 36 thereof for reflecting or directing the light.

The tubes of the present invention may be used with the tungsten heater described in copending patent application Serial No. 16,898 for Microwave Excited Spectrum Tube with Internal Heater filed March 22, 1960.

In addition to more eflicient collection of light on the entrance slit of a spectrometer, it has been demonstrated that the present device provides excitation of higher energy states than tubes of conventional design, thereby emitting a richer spectrum, and provides new lighting sources. Improvements of 20 to 40 fold increase in intensity over conventional cylindrical tubes or the like heretofore known are available with the present device.

Obviously many modifications and variations of the present invention are possible in the light of the above teachings. It is therefore to be understood that within the scope of the appended claims the invention may be practiced otherwise than as specifically described.

What is claimed is:

1. An electric discharge light source comprising a ho1 low transparent glass body having a very narrow interior chamber of very thin slit-like cross-section, the configuration of said very narrow chamber being substantially 3 like that of said glass body for providing a thin line of light at one narrow end thereof, said chamber containing a gas to be excited by electrodeless exterior excitation, means for sealing said gas within said glass body and means completely outside said glass body for exciting the gas within said narrow chamber, excitation of high energy states from 20 to 40 fold improvement in intensity being available for spectrometry and the emission of a rich spectrum being provided at the narrow end of said chamber for end-on viewing.

2. A light source as in claim 1 wherein the gas within said chamber is microwave excited by said means completely outside said glass body.

:3. An electric discharge light source comprising a hollow transparent glass body having a very narrow interior chamber of very thin slit-like cross-section, the configuration of said very narrow chamber being substantially the same as that of said glass body, said chamber hav ing its narrowest cross-sectional dimension in the order of inch, an excitable gas within said chamber and providing an intense thin line of light at a narrow end of said chamber, means for sealing said gas within said glass body and means outside said narrow chamber for exciting the gas within said narrow chamber, said light source being capable of excitation to high energy states from 20 to 40 fold improvement in intensity and emission of a rich spectrum at the end of said narrow chamber available for use in spectrometry.

4. A high energy light source as in claim 3 wherein said means for exciting the gas includes electrodes.

5. A device as in claim 3 wherein said means for exciting said. gas includes a filament.

6. A device as in claim- 3 which is electrodeless and wherein said gas is excited by a microwave beam source.

7. A device as in claim 3 wherein a gas reservoir is provided to assure a suitable. supply of gas within said narrow chamber.

8. A device as in claim 3 wherein said narrow chamber is flat for providing a thin line of light at one end thereof.

9. A device as in claim 3 wherein said narrow chamber is curved and said slit-like cross-section is curved.

10. A device as in claim 3 wherein said narrow chamber is silvered on one broad surface thereof.

11. A device as in claim 3 wherein said narrow chamber is coated with a fluorescent material on one broad surface thereof.

12. The method of fabricating a spectrometry light source tube having a very thin cross-section for obtaining a thin line of light of high intensity comprising inserting a thin strip of tungsten within a section of quartz tubing, heating said tubing until it is flattened against said tungsten strip, cooling said flattened tube and withdrawing said tungsten strip where possible, placing said tube in acid until said tungsten strip is loose enough to be removed from said tube.

Marden Sept. 9, 1941 Foerste Apr. 20, 1943 

